Q&A: A Forum for Green Building Experts and Beginners

[Click map to enlarge]

Please register for a free account or sign in to ask and answer green building questions.

The usual rules of courtesy apply:
1. Be nice.
2. If you can't be nice, be polite.
3. If you can't be nice or polite — well, please be brief.

To attach a photo or illustration:
Under the box labeled "More explanation," look for the words "File attachments."
Click that, and you should be able to attach a photo.

Thanks for joining the conversation!

18 Answers

We are building a straw-bale house with steel bones in Sacramento, CA in spring 2015 and I'd love to get some insights from the community! We are pretty far along into the design process, but with nothing purchased as of yet I'd love to get some input before we put our money where our mouths are.

Our goal is to have a (mostly) passively heated and cooled home in (relativity) temperate Sacramento, CA. Passivhaus would be nice but it's an aspiration rather than a goal. Our lot has a number of trees for shade that we plan to utilize, especially in the western aspect.

Asked By Nick Campbell | Aug 26 14
3 Answers

I would like to add foam board to the exterior of my house to beef up the R value. The walls currently are 2x6 with fiberglass batts and plastic sheeting as a vapor barrier between the studs and drywall. Most of the stuff I've seen says you don't want a vapor barrier on the inside so your sheeting can dry to the inside but I haven't found much information on what to do if the vapor barrier is already in place. Thanks!

Asked By Jacob Roark | Aug 28 14
17 Answers

I was speaking with my passive house consultant the other week, and she expressed concerns about boring critters and subsurface rigid insulation. She had such an experience with some insulation in her garden (It was put in one season and removed at a later time as she got back to completing the project.)
Now, I know all about the ate/termite protection used in these insulation products, but what about larger critters that would love to have a warm dry home?

Asked By Steve Young | Aug 16 14
1 Answer

I've seen the Geyser RE mentioned on this forum numerous times, so I am hoping someone can help me troubleshoot my unit. I installed one this summer, connected to a new 80 gallon State electric water heater. It worked for a couple of days and then starting tripping the circuit breaker. It was a 15 amp circuit (I was using a 25' 12 gauge extension cord to reach it which tech support had ok'd beforehand). I thought maybe the combo of a 15 amp circuit and the extension cord was the problem, so I wired a new dedicated 20 amp circuit right next to the unit, but the problem persisted.

Asked By austin jamison | Aug 28 14
6 Answers

Hi all,

New owner of a 1 1/2 level cape here. Finished upstairs. Zone 5. I'm experienced with home renovations and DIY, but new to Capes.

Trying to bring upstairs environmentals in line with lower level conditioned home temps year round without running the mechanicals 24 /7.

No insulation to speak of. No ventilation. No vapor barrier. Planning to make the attic "outside space".

I've blocked all of the underfloor joist bays, sealed all chases and penetrations, insulated the kneewall hatches very well, etc. This has helped a lot.

Next steps:

Asked By M Welch | Aug 27 14
6 Answers

This is something that as passed a few times in my background brain processes,

How does SHG on exterior cladding/glass influence heatloss ??

If glazings specs 50%VT , a part of the remaining 50% must be converted to heat?

If exterior cladding on a building is black, and sun is shinning on the south face,
it must affect the heatloss greatly for the shined on walls ??

As an example, let's assume a building up here cold north.
20c inside 0c outside.
Sun shines on a large flat south wall that was cladded with a black painted steel sheets finish.

Asked By Jin Kazama | Aug 28 14
14 Answers

I would like to ask the math pros here on how to calculate heat loss from infiltration rates.

I have seen so many different formulas in the last weeks that my head is hurting.

So would like to have a "reliable" formula that could be used in my never-ending expanding excel spreadsheets !

Something with at least a little bit of proven precision, that could be used to effectively get additional heat loss using door blower results or planned target value.

Links or straight formula please :)

Asked By Jin Kazama | Aug 25 14
10 Answers

I would like to decide on putting in solar panels to reduce energy costs.

I have read about the next generation solar panels not being to far off.

Question: Would it be better to install current solar panels or wait for the new type that will be coming shortly?

Asked By John Alberti | Aug 26 14
12 Answers

I'm in zone 4 (NYC suburb) and the original house is a 2 1/2 story wood framed house heated by gas fired one pipe steam. Cooling is from window units. Our addition (currently rough framed and dryed in) is two stories with an 18' x 15' exterior footprint. 3 foot block stem walls make the lower level slightly smaller than the upper. The upper level, which connects to our main floor, will be our new kitchen, and the lower level, which connects to a walkout basement, will be a play/TV room.

Asked By mike mcguirk | Aug 25 14
3 Answers

I am in the process of trying to determine how much strapping spacing is needed on a ceiling to support 22" of blown-in cellulose above it. The strapping is 1x4 pine and I plan on spacing 16" OC whixh makes the space between supports of 12". The strapping is holding 6 mil poly up against the bottom chord of the truss. There will be some ballooning of poly downward in those squares between truss and strapping. 5/8" Sheetrock will be used up against strapping to finish. Thanks in advance.

Asked By Matthew Michaud | Aug 26 14
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!